1. Field of the Invention
This invention relates to the application of herbicides and more particularly to an apparatus for selective application of herbicides.
2. Description of the Prior Art
A new type of liquid herbicide has recently been developed which is sometimes referred to as a systemic herbicide. A systemic herbicide is one which will be absorbed by the vegetation to which it is applied and will permeate the vegetation to kill the root systems without affecting the soil in any way. Systemic herbicide and other types of herbicides may be applied by a conventional spray method when complete destruction of all plant life in a sprayed area is desired. However, selective herbicidal tasks such as weeding operations, require that herbicides be selectively applied only to the vegetation which is to be destroyed, and this, of course, eliminates the usage of spraying application techniques.
A special herbicide applicator which is designed primarily for use with systemic herbicide has been developed for use in cultivated fields and this device is in the form of a trailing wick that is attached to a tractor, or other farming mechanism. The special trailing wick applicator is carried by the farm machine so as to follow the furrows between the crop plants. In this manner, the trailing wick applicator will wipe the herbicide on the weeds that are growing in the furrows only in that the trailing wick cannot be allowed to come into close proximity with the crop plants. Thus, such a device is limited in its use in that it cannot be employed to kill vegetation that is proximate any plants that are not to be killed, due to the fact that the trailing wick applicator cannot be controlled with any desired degree of accuracy.
A hand held herbicide applicator has been developed for selective application purposes, and that applicator is fully disclosed in U.S. Pat. No. 4,027,986. Briefly, this particular prior art applicator comprises a reservoir handle with a fill and vent control plug on its upper end and an applicator head on its other end. The applicator head is a bell-shaped enlargement which is filled with a foam rubber material and has its lower open end wrapped with a carpeting material. The herbicide flows from the reservoir handle through an orifice and saturates the foam rubber and the carpeting material. Although this applicator can be used for selectively applying herbicide on vegetation, its usage is limited to a more or less dabbing type of application due to the particular head configuration. The applicator head is designed primarily for dabbingly applying the herbicide on newly cut tree trunks to kill the root systems thereof and cannot practically and efficiently be used to wipingly apply herbicide to, for example, weeds which have outgrown slower growing grasses and the like, and it is awkward to use in between closely spaced crop plants.
Therefore, a need exists for a new and improved hand held apparatus for selective application of liquid herbicides, with the apparatus overcoming some of the shortcomings of the prior art.